Sizing Composition for Charges Used in Thermoplastic Polymeric Material Reinforcement, Reinforced Polymeric Materials and Method of Manufacture

ABSTRACT

The invention relates to an aqueous sizing composition for reinforcing charges, preferably glass fibers, comprising a silane coupling agent, an epoxy film forming polymer comprising 2-8 reactive epoxy groups per chain and compatible with thermoplastic polyester matrix resin selected from PET and PBT, and a hypophosphite in an amount of 5 to 30 w % of the composition, preferably 7 to 25 w %, more preferably 10 to 20 w % and most preferably 12 to 18 w % of the composition. A thermoplastic polyester resin reinforced with glass fibers coated with a sizing composition of the invention shows improved resistance to staining and improved tensile elongation at break. The sizing composition further improves processability of the sized fibres.

BACKGROUND OF THE INVENTION

The present invention relates to sizing compositions for reinforcementmaterials or charges, such as particulate charges including glass orsand, natural fibers, such as bamboo fibers, or mineral fibers, morespecifically basalt, carbon or glass fibers, intended to be used asreinforcing material for polymeric matrix material, more specificallythermoplastic polymeric materials such as thermoplastic polyestermaterials, more specifically polyalkylene terephthalates such aspolyethylene terephthalate (PET) or polybutylene terephthalate (PBT).The present invention further relates to reinforcing materials, morespecifically mineral fibers, preferably glass fibres, treated with thesizing composition of the invention and to thermoplastic polymericmaterials such as polyester materials, more specifically polyalkyleneterephthalates, such as polyethylene terephthalate (PET) or polybutyleneterephthalate (PBT), reinforced with such charges, more preferably glassfibers, treated with the sizing composition of the invention. Finally,the invention relates to processes for treatment of reinforcingmaterials and for the manufacture of reinforced polyester matrixmaterial.

It is generally known to improve mechanical properties of thermoplasticmaterials by incorporating a reinforcing material or charge, oftenparticulate mineral charges, such as glass or sand, or natural ormineral fibers, including carbon fibers or glass fibers. Mineral fibersand more specifically glass fibers are produced by continuously flowingmolten mineral (rocks or glass) through so-called bushings. In the caseof glass fibers, different qualities of glass may be used; the mostcommon quality is the so-called E-glass known as electrical glasscommonly used for insulators etc., for example Advantex glass availablefrom Owens Corning. The obtained filaments may then be gathered intobundles and chopped at desired lengths before being mixed with a matrixresin.

It has become apparent; however, that the reinforcing properties of suchcharges or reinforcing materials may be optimized by improving theadhesion between the reinforcing material and the polymeric matrix it isintended to reinforce. It has thus been suggested to treat thereinforcing material with a so-called size or sizing composition. Thissizing composition is intended to render the reinforcing material morecompatible with the polymeric matrix material to be reinforced and toimprove the processability of the relevant reinforcing material.

In the following description, reference is made to glass fiber charges.It is emphasized herewith that the described technology also applies toother mineral fibers, such as carbon fibers and fibers made of basalt orother rocks, and the present description and claims are not limited toglass charges or glass fibers.

In the case of fibers, it is preferable to treat the fibers before theyare arranged into bundles of a multitude (from several hundreds toseveral thousands) of individual continuous fibers, which may then bechopped in desired length and dried and mixed with melted polymericresin material. This mixing step may for instance be effected in anextruder, thus destroying the integrity of the chopped bundle segments,dispersing the fiber segments throughout the molten resin and formingfiber/resin pellets which may then be further processed into compositearticles.

There is in recent times an increasing need in thermoplastic resin fordifferent applications. Also fiber reinforced thermoplastic resins areincreasingly gaining interest in molding applications. In order toincrease its productivity, the compounding industry seeks to improve thecompounding extruder throughput and also has a tendency to move towardsthe use of so-called mega-compounders. This requires increasedquantities of fiber to be fed per time unit to the extruder withconcomitant increased tendency of fuzz formation which in turn affectsfiber transport.

In more recent processing equipments, the chopped reinforcing fiberbundles are transported by pneumatic systems which tend to dry thechopped fiber bundles, thus further increasing the risk of fuzzformation.

In the case of fibers, the sizing compositions used to render themcompatible with polyester matrix resins have a tendency to render thetreated fibers prone to electrostatic charging under certain conditions.Electrostatic charging further affects the transport or feeding of thefibers.

The assembling of article parts made of reinforced thermoplastic resinmore and more occurs by snap fitting which requires improved mechanicalproperties such as improved elongation at break.

Furthermore, despite all progress made in stabilizing thermoplasticresin material, there is still a need to improve the stability tostaining or discoloration, more particularly staining or discolorationof reinforced thermoplastic resin material, particularly due to thesizing composition applied on the reinforcing material.

Hypophosphite salts are known by the skilled artisan to improve certaincharacteristics of polymer resins containing them.

JP-2116648 proposes to spray hypophosphorous acid or a salt thereof(e.g. calcium hypophosphite) on a glass fiber bundle in an amountranging from 0.05 to 1.5% by weight of the fibers in order to improvethe staining resistance of the resin matrix when such treated fibers areused to reinforce a thermoplastic resin other than polyphenylenesulfide, selected from a group comprising thermoplastic polyesterresins, such as PBT, polyolefin resins or polyamide resins.

Similarly, EP-0344436 proposes to incorporate hypophosphorous acid or asalt thereof in a polyphenylene sulfide resin in an amount ranging from0.01 to 5% by weight of the resin composition in order to improve theimpact resistance or staining resistance. In a preferred embodiment,hypophosphorous acid or a salt thereof is attached on the glass fiberbundle in an amount ranging from 0.05 to 1.5% by weight of the fibers inorder to improve the staining resistance of the polyphenylene sulfideresin matrix when such treated fibers are used to reinforce said resin.

EP-0381125 relates to polymer compositions, such as sizing compositions,with improved oxidative stability. In order to improve oxidativestability, it is suggested to add small amounts of antioxidants orreducing agents, below 3% by weight of the sizing composition, amongwhich sodium hypophosphite is considered a suitable “low temperatureantioxidant”. Polymeric compositions are disclosed in a very generalway, apart from the preferred embodiments of Table A and the exemplifiedcompositions of Table 1. None of these, however, disclose or suggest thecompositions of the invention nor how to conceive a sizing compositionthat further improves mechanical properties, such as elongation atbreak, of a mineral reinforced PET or PBT matrix, nor how to reduce fuzzformation and electro-static behavior of sized fibers.

U.S. Pat. No. 6,280,571 suggests to prevent thermal degradation ofcertain water-soluble polymers by addition of phosphorous orhypophosphorous acid or a salt thereof in an amount of 0.01-75 w %,based on the total weight of polymer plus stabilizer.

WO95/25074 discloses glass fibers treated with a sizing compositionhaving an organo functional inorganic coupling agent (around 1 to around30% by weight of the non-volatiles of the composition), a polyolefincompatible film forming acid-modified polyolefin (from around 50 toaround 90% by weight of the non-volatiles of the composition), one ormore stabilizers (from around 1 to 25% by weight of the non-volatiles ofthe composition) including hypophosphites, and a carrier such as water.Other additives such as emulsifiers, antifoams and surfactants may alsobe added. It is suggested that such treated fibers may advantageously beused to reinforce polypropylenes, polyethylenes and polyalkyleneterephthalates, polyamides and others.

U.S. Pat. No. 6,207,737 of the same patent family as WO95/25074 morespecifically discloses an aqueous sizing composition for glass fibersused to reinforce for instance polyesters such as PBT and PET,comprising a coupling agent, e.g. functional organosilanes, an acid oracid anhydride modified polyolefinic film-forming material and astabilizer effective against oxidizing phenomena, e.g. hypophosphitesselected from alkali metal hypophosphites, alkaline earth metalhypophosphites, ammonium hypophosphite and mixtures thereof, preferablysodium and potassium hypophosphite, and possibly surfactants.

U.S. Pat. No. 5,646,207 of the same patent family discloses similarcompositions. While the film forming polymer may be selected from a listof polymers, the examples only disclose acid modified polypropylenepolymer. The document does not disclose the specific compositions of theinvention nor how best to apply them as size compositions on mineralcharges in order to achieve the aims of the invention; in any case theexemplified size compositions are clearly different from the inventioncompositions and are applied as a single mixture. It does not discloseeither how to reduce fuzz formation and how to improve electro-staticbehavior of sized fibers. Even if different mechanical properties ofreinforced polymer matrices are evaluated in the examples, the matrixpolymer chosen is different from any matrix polymer envisaged in thepresent invention, and any change in mechanical properties can hardly beattributed to a precise factor or component of the mixture.

Similarly, EP-0356655 also relates to a chemical treatment for fibersand use of such fibers in the reinforcement of polymer matrices. Thesizing compositions disclosed do not show the same composition as perthe present invention. Furthermore, they contain hypophosphite in lowquantities ranging from 0.001 to 1% by weight, as an antioxidant. Hereagain, the document does not disclose how to reduce fuzz formation andhow to improve electro-static behavior of sized fibers. U.S. Pat. No.5,130,198 discloses a sizing composition for glass charges in polyestermatrices, such as PET and PBT, with improved oxidative stabilitycomprising a thermoplastic matrix-compatible polymer, more specificallya combination of polyurethane and epoxy polymers (when the matrix isPBT), an organofunctional silane glass resin coupling agent, a metalchelating agent and an antioxidant such as hypophosphite salts andpossibly fiber lubricants and/or epoxy polyester processing aids andcrosslinking agents. The antioxidants may be incorporated into thecoating composition or added in a secondary treatment after the coatinghas been applied as size to the reinforcing substrate. The hypophosphiteantioxidant ranges from about 0.001 to about 2 w % of the non-aqueoussolids of the sizing composition, preferably up to about 1 w % and morepreferably from 0.1 to about 0.3 w % of the composition when sodiumhypophosphite is used. Assuming that the coating of aqueous sizingcomposition on the fibers is (as generally the case) from about 0.1 toabout 2% of fiber weight (LOI—loss on ignition), this equates to amaximum metal hypophosphite content of 0.04% of fiber weight.

WO2004/110948 discloses a two-part sizing composition comprising a sizecomposition and a binder composition, wherein the size compositioncomprises a coupling agent, e.g. a silane coupling agent, a cationicsoftener, a wetting agent and possibly further adjuvants, and whereinthe binder composition comprises a non-ionic aqueous emulsion of anepoxy-ester resin and/or of a flexible epoxy resin, an aqueouspolyurethane dispersion and possibly other adjuvants. The bindercomposition does not comprise any aminosilane coupling agent. The sizecomposition may further comprise an antistatic agent such as apolyoxy-alkylene-amine. Some of the surfactants may also have anantistatic effect.

It is also worth noting that WO2009/062137 discloses aqueous sizingcompositions for glass fibers, comprising an acid-amine component, theacid-amine component comprising molecules of at least one amineassociated with molecules of at least one phosphorous-containing acidand/or sulfur containing acid. The phosphorous containing acid may behypophosphorous acid. The film-forming polymer is different from the onechosen in accordance with the invention. Examples L to Q neverthelesscontain sodium hypophosphite in relatively high amounts. According tothe Table II, however, sizing compositions with high levels of sodiumhypophosphite show increased fuzz formation, a problem the inventionprecisely seeks to resolve.

EP-1452567 discloses a flame-retardant resin composition comprising abase resin which may be a PBT or PET resin, a flame retardant which maybe a hypophosphorous ester, and a glass fiber optionally treated with asizing agent containing a Novolac epoxy resin.

OBJECTS OF THE INVENTION

The present invention seeks to further improve the resistance tostaining and/or discoloration of thermoplastic polyester matrixcompositions, such as PBT and PET, reinforced by mineral reinforcingcharges, such as glass or sand charges, or natural or mineral fibers,more preferably glass fibers.

Another object of the invention is to further improve the mechanicalproperties, more specifically elongation at break, of thermoplasticpolyester resin matrixes reinforced with mineral reinforcing charges,such as glass or sand charges, or natural or mineral fibers, morepreferably glass fibers. As explained earlier above, polyester resinmatrices are more and more looked at for the production of articlescomposed of parts to be assembled by snap fitting. In order to avoidbreakage of the relevant parts at the assembling stage, a sufficientelongation at break is required.

Furthermore, the present invention seeks to enhance the electrostaticproperties of treated fibers, thus improving the handling, transportand/or feeding efficiency of the treated fibers and reducing themaintenance costs of relevant equipment.

SUMMARY OF THE INVENTION

The present invention provides an aqueous sizing composition forreinforcing charges, comprising a silane coupling agent, an epoxy filmforming polymer compatible with polyester matrix resin and ahypophosphite, the hypophosphite being in an amount of 5 to 30 w % oftotal solids of the composition, preferably 7 to 25 w %, more preferably10 to 20 w % and most preferably 12 to 18 w % of the composition.

The sizing composition of the invention may advantageously comprisefurther components, such as polyurethanes, and/or surfactants and otheradjuvants commonly used in such sizing compositions and known to theperson skilled in the art.

Silane coupling agents are well known in the art for having been usedfor a long time already. They facilitate adhesion of the organicallybased sizing composition and hence of the film forming polymer to thepolar reinforcing charges, more particularly glass fibers. According toa preferred embodiment, the silane coupling agent is an amino functionalsilane. According to another preferred embodiment of the invention, thesilane coupling agent is an organic epoxy silane.

The thermoplastic polyester matrix resin considered here isadvantageously a polyalkylene terephthalate, preferably PET or PBT.According to a preferred embodiment, the epoxy film forming polymercompatible with said polyester matrix resin comprises 2 to 8 reactiveepoxy groups per chain, even more preferably 3 to 8 reactive epoxygroups per chain, and is advantageously selected from epoxy phenolnovolac EPN or epoxy cresol novolac ECN type resin or mixtures thereof.The epoxy groups may be arranged as a star on a backbone chain orregularly along a backbone chain.

The hypophosphite is selected among hypophosphite salts such as metalhypophosphites, alkaline earth metal hypophosphites, ammoniumhypophosphite and mixtures thereof. Most preferred are sodium andpotassium hypophosphite. The term hypophosphite as used herein is notmeant to include esters of hypophosphorous acid. For the sake ofclarity, it is emphasized that the term hypophosphite salt also includesthe combination in the mixture of the hypophosphorous acid with a cationprovider to form the corresponding salt.

It should be emphasized here that none of the prior art documentsreferred to above teaches the combinations now found to constitute theinvention.

According to the invention, the sizing composition may be a multi-partsizing composition comprising a size composition and a bindercomposition, the hypophosphite being comprised in an amount of 5 to 30 w% of the total solids of the composition, preferably 7 to 25 w %, morepreferably 10 to 20 w % and most preferably 12 to 18 w % of the totalcomposition, wherein the size composition comprises the silane couplingagent, and the binder composition comprises the epoxy film formingpolymer compatible with polyester matrix resin. The size composition mayfurther comprise additional components, such as film formingpolyurethanes, and/or surfactants and/or lubricants and/or otheradjuvants commonly used in such sizing compositions. The bindercomposition may further comprise additional components, such as filmforming polyurethanes, and/or surfactants and/or lubricants and/or otheradjuvants commonly used in such binder compositions. The bindercomposition does not comprise any silane coupling agent. Thehypophosphite may be included in the size composition and/or in thebinder composition and/or constitute a third part of the sizingcomposition. A multi-part sizing composition according to the inventionmay be applied in multiple steps on the relevant matrix reinforcingcharges, thus first applying the size composition comprising thecoupling agent, for instance by kiss roll applicator or spraying,followed by application of the binder composition. Preferably, thehypophosphite is applied yet separately in a third step. It has beenfound that when applied as overcoat, preferably after drying of fibers,the effect of the hypophosphite, meaning the anti-static effect and theeffect on mechanical properties, is optimized. None of the prior artdocuments mentioned in the introduction in any way suggest that thesizing composition be in multiple parts, even less so suggest to applythe hypophosphite as an overcoat.

For the sake of clarity, the words “sizing composition” are usedthroughout the description and claims to designate a composition fortreatment of reinforcing charges. The words “size composition” are usedthroughout the description and claims to designate a part of amulti-part sizing composition.

It has been found that the sizing composition of the invention providesimproved properties to the thermoplastic polyester matrix resinreinforced with charges coated with the relevant sizing composition. Theinvention thus also relates to coated reinforcing charges, preferablymineral charges, more preferably glass fibers, and to a thermoplasticpolyester matrix resin reinforced with charges, particulate or fibers,more preferably mineral charges, more specifically glass fibers, coatedwith a sizing composition of the invention. The improved mechanicalproperty essentially consists in the elongation at break. The sizingcomposition of the invention further improves the matrix resistance todiscoloration or staining. Finally, it has been found that fibers coatedwith the sizing composition of the invention show improved handling andprocessability because of a reduced tendency to form fuzz in pneumatictransport or feeding systems and because of reduced tendency toaccumulate electrostatic charges. Electrostatically charged fibersegments further promote fuzz formation thereby affecting the transportor feeding systems. More particularly pneumatic feeding systems sufferfrom accumulated fuzz that may progressively obstruct feeding tubes,thus reducing the flow of fiber material with the result of irregularfiber feeding into the matrix polymer and/or reduced production speed.Furthermore, such inconveniences require regular and/or multipleinterruption of the production equipment for maintenance purposes.

None of the above mentioned prior art discloses or suggests any sizingcomposition as herein described for treatment of reinforcing charges,more specifically mineral charges, preferably glass fibers, intended foruse in thermoplastic polyester matrices, such as PET and PBT, thatcomprises a coupling agent, a film forming epoxy resin comprisingreactive epoxy groups and a hypophosphite in an amount sufficient tohave an antioxidant, staining-resistance effect as well as to improvethe mechanical properties, more specifically the elongation at break, ofthe reinforced polyester matrix resin.

Furthermore, no suggestion can be found in the above referenced priorart on how to improve the electrostatic behavior of fibers treated witha sizing composition comprising film forming epoxy polymers that enhancethe compatibility between the reinforcing charges and the thermoplasticpolyester matrix resin.

The above-mentioned advantages and other features of the invention willbe further detailed and explained herein below with reference toattached figures and examples.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will be explained in more details below, withreference to the following drawings:

FIG. 1 is a schematic representation of an equipment designed to showstatic/antistatic properties;

FIG. 2 shows the effect of addition of sodium hypophosphite on theTensile Elongation at Break of normalized PBT samples.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an aqueous sizing composition forreinforcing charges, comprising a silane coupling agent, an epoxy filmforming polymer comprising 2-8 reactive epoxy groups per chain, saidepoxy polymer being compatible with thermoplastic polyester matrix resinand a hypophosphite in an amount of 5 to 30% by weight of total solidsof the composition, preferably 7 to 25 w %, more preferably 10 to 20 w %and most preferably 12 to 18 w % of the composition.

Suitable silane coupling agents for use in the sizing compositions ofthe invention are advantageously selected from amino functional silanes,such as those available from Momentive, Dow Corning Inc, ShinEtsu,Gelest or Wacker, including but not limited to monoamino-silanes,amino-propyl-triethoxy-silane, gamma-amino-propyl-triethoxy-silane,amino-propyl-trimethoxy-silane, amino-propyl-methyl-dimethoxy-silane,amino-propyl-methyl-diethoxy-silane, aminopropylsilsesquioxane,aminopropyl-diisopropyl-ethoxy-silane,amino-propyl-dimethylethoxy-silane,amino-propyl-tris(methoxyethoxyethoxy)-silane,bis(trimethoxysilylpropyl)amine, aminobutyl-triethoxy-silane,butylaminopropyl-trimethoxysilane, aminoundecyl-triethoxy-silane,aminoneohexyl-trimethoxy-silane, aminoneohexyl-methyldimethoxy-silane,benzylamino-silane, N-phenyl-aminopropyl-trimethoxysilane,N-phenyl-aminomethyl-trimethoxysilane,aminohexyl-methyldimethoxy-silane, ethylaminoisobutyl-trimethoxy-silane,ethylaminoisobutyl-methyldiethoxy-silane,methylaminopropyl-trimethoxy-silane,methylaminopropyl-methyldimethoxy-silane,3-(1,3-dimethylbutylidene)amino-propyltriethoxy-silane,phenylaminomethyl-methyldimethoxy-silane,phenylaminomethyl-triethoxy-silane,(N-allylamino)propyl-trimethoxy-silane,bis(hydroxyethyl)-aminopropyl-triethoxy-silane,diethylaminomethyl-triethoxy-silane,diethylaminopropyl-trimethoxy-silane,dimethylaminopropyl-trimethoxy-silane,N-ethyl-3-trimethoxysilyl-methylpropamine,cyclohexyl-amino-methyl-methyldiethoxy-silane,cyclo-hexyl-amino-propyl-trimethoxy-silane,cyclohexyl-amino-methyl-triethoxy-silane,trimethoxysilylpropyl-trimethylammonium chloride,octadecyldimethyl-(trimethoxysilylpropyl)ammonium chloride,N,N-didecyl-N-methyl-N-(trimethoxysilyl-propyl)-ammonium chloride,tetradecyldimethyl(trimethoxysilyl-propyl)-ammonium chloride,N-(trimethoxysilylethyl)-benzyl-N,N,N-trimethyl-ammonium chloride,N-(trimethoxysilylpropyl)-isothiouronium chloride,bis(triethoxysilylpropyl)-amine, bis(trimethoxy-silylpropyl)-amine,bis(methyldiethoxysilylpropyl)-amine,bis(methyldimethoxysilylpropyl)-N-methylamine, diamino-silanes,amino-ethyl-amino-propyl-trimethoxy-silane,amino-ethyl-amino-propyl-triethoxy-silane,amino-ethyl-amino-propyl-methyl-dimethoxy-silane,aminoethyl-aminopropyl-trimethoxysilane,aminoethyl-aminopropyl-triethoxysilane,aminoethyl-aminoisobutyl-methyldimethoxy-silane,aminoethyl-aminoisobutyl-dimethylmethoxy-silane,aminohexyl-aminomethyl-triethoxysilane,aminohexyl-aminopropyl-trimethoxysilane,aminoethyl-aminoundecyl-trimethoxysilane,(aminoethylaminomethyl)-phenylethyl-trimethoxysilane,N-(2-aminoethyl)-3-aminopropyl-silanetriol,bis[(trimethoxysilyl)propyl]-ethylenediamine,bis[(triethoxysilyl)propyl]-urea,N,N-dioctyl-N-triethoxysilylpropyl-urea,3-(N-styrylmethyl-2-aminoethylamino)-propyl-trimethoxysilanehydrochloride, benzylaminoethyl-aminopropyl-trimethoxy-silane,triamino-silanes, diethylene-triamino-propyl-trimethoxy-silane,(trimethoxyetylpropyl)-diethylene-triamine,ureidopropyl-trimethoxy-silane, ureidopropyl-triethoxy-silane,2-(4-pyridylethyl)-triethoxy-silane,2-(2-pyridylethyl)thiopropyltrimethoxy-silane,2-(4-pyridylethyl)thiopropyl-trimethoxy-silane,N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole,acetamido-propyltrimethoxysilane,N-[5-(trimethoxysilyl)-2-aza-1-oxo-pentyl]caprolactam,N-allyl-aza-2,2-dimethoxysilacyclopentane,N-aminoethyl-aza-2,2,4-trimethylsilacyclopentane,N-(3-aminopropyl-dimethylsila)-aza-2,2-dimethyl-2-silacyclopentane,N-butyl-aza-2,2-dimethoxysilacyclopentane,2,2-dimethoxy-1,8-diaza-2-silacyclooctane,N-methyl-aza-2,2,4-trimethylsilacyclopentane and polyazamide silylatedaminosilane.

Other suitable coupling agents are organic epoxy silanes, advantageouslyselected from cycloaliphatic epoxy silanes, such asepoxycyclohexylethyltrimethoxysilaneepoxycyclohexylethyltriethoxysilane, and glycidoxysilanes, such asgamma-glycidoxypropyltrimethoxy-silane,gamma-glycidoxypropyltriethoxysilane,gamma-glycidoxypropyl-methyldimethoxysilane orgamma-glycidoxypropyl-methyldiethoxysilane.

The composition of the invention may comprise one or more of the abovementioned coupling agents in an amount of from 1 to 20% by weight oftotal solids in the sizing composition, preferably 1 to 15% by weight oftotal solids, more preferably 2 to 10% by weight, most preferably 2 to8% by weight of total solids in the sizing composition.

Film forming epoxy resins comprising reactive epoxy groups, morespecifically epoxy novolac type resins are known film formers compatiblewith polyester matrix resins such as PET and PBT. Preferred epoxy resinscomprise 2 to 8 functional epoxy groups per chain, even more preferably3 to 8 functional epoxy groups per chain, and are advantageouslyselected from epoxy phenol novolac EPN type resins and epoxy cresolnovolac ECN type resins and mixtures thereof. These materials areadvantageously processable in water emulsions, preferably non-ionicemulsions. Commercial emulsions are available from Hexion, such asRSW-4254 (with a functionality of about 3.6) and EPI-REZT™ type resins,more preferably EPI-REZ-6006-W-70 with a functionality of about 6 andDPW-5108 with a functionality of about 8, and from Adeka, such asEM-0514 and EM-0517, and from Cairn, such as Filco™ 345, 74005, 7801 and7802. Other examples are Neoxil type aqueous emulsions of epoxy esterresins from DSM, such as Neoxil 962D, Neoxil 8294, Neoxil 4298 (a 55%epoxy-bis-phénol A type resin), EMX-063 which is an epoxy film formerwith a 55% non-volatile fraction and 6.3 epoxy functionality or EM-054,an epoxy film former with a 50% non-volatile fraction and 6.3 epoxyfunctionality, both from Adeka.

The film forming epoxy polymer, compatible with polyester matrix ispresent in the compositions of the invention in an amount ranging from25 to 80 w % of the total composition, preferably 30 to 70 w %, morepreferably 35 to 67 w %, most preferably 40 to 60 w % of the totalcomposition.

The hypophosphite may be selected from hypophosphorous salt such as,metal hypophosphites, alkaline earth metal hypophosphites, ammoniumhypophosphite and mixtures thereof or from the combination ofhypophosphorous acid with relevant base to form such salts. Mostpreferred are sodium and potassium hypophosphite; sodium hypophosphitemonohydrate being the most common product available on the market.

The compositions of the invention may further include film formingpolymers such as polyurethanes. They are generally used to improve fiberintegrity and their level is kept low in order not to substantiallyaffect the mechanical properties of the matrix and/or final compoundmaterial. They are selected in order to enhance compatibility with thematrix resin, thus reducing potential negative effect on mechanicalproperties. Any type of polyurethane dispersion stable in the given pHrange and having good film forming properties is suitable. Preferredpolyurethane polymers are so-called polyether based or polyester basedpolyurethanes. Commercial polyether based polyurethanes are availablefrom DIC (examples are 1050-NE, 1310NE, 8510, 1940NE, 2260NE, V3621,V3624, V3625 and V3626), from Adeka (HUX-280) and from Bayer (BaybondPU406; Baybond RSC 1187). Commercial polyester based polyurethanes areavailable from DIC (examples are 1640NE, 1672NE, 1980NE, HS-770, 2210,2220, V3433, V3595), from Adeka (HUX-817 and HUX-830) and from Bayer(Baybond VLS-2277). They are advantageously comprised between 10 and 50%by weight of the total composition, preferably between 10 and 40 w %,more preferably between 12 and 35 w %.

Compositions of the present invention may also include other adjuvantsknown to the person skilled in the art, such as lubricants, surfactantsor surfactant mixtures or other materials like waxes. Suitablelubricants may include polyoxy-alkylene-amines as are available fromHuntsman Corporation. Suitable surfactants preferably include non-ionicsurfactants. Examples of such surfactants are octylphenol ethoxylate(e.g Triton X100 from Union Carbide), ethylene oxide/propylene oxideblock copolymers of the Pluronic series available from BASF or of theSynperonic series available from ICI, or fluoroalkyl alcohol substitutedpolyethylene glycol. The skilled person will be able to adjust thecomposition with relevant concentrations of such products as lubricantsand surfactants knowing that the purpose is to adapt the surface tensionsuch as to reach a suitable wetting of the fibers, and further knowingthat surfactants are already included in the relevant emulsions used toform the compositions of the invention.

The composition of the invention may further comprise one or morebiocides for certain applications as may appropriately be selected bythe skilled person.

The sizing composition may be prepared by addition of the relevantcomponents in appropriate amounts simultaneously or in sequence, as theskilled person will best determine. It is generally preferred to add therelevant components into water to prepare the sizing composition. Therelevant components are preferably already diluted in water beforeaddition into the aqueous sizing composition.

The sizing composition may be applied in a manner known per se to thereinforcing charges, preferably fibers. Conventional methods includeapplication by rolling, brushing and spraying. More specifically in thecase of glass fibers, the sizing composition is advantageously appliedto the fibers during their formation or the wet chopping operation. Theamount of sizing composition applied to glass fibers generally rangesfrom 0.4 to 1.4% by weight of glass charge calculated as LOI (loss onignition).

According to an alternative advantageous embodiment of the invention,the sizing composition may be a multi-part composition comprising a sizecomposition which comprises the silane coupling agent, a bindercomposition which comprises the epoxy film forming polymer compatiblewith the polyester matrix resin but essentially no coupling agent, and ahypophosphite being comprised in an amount of 5 to 30 w %, preferably 7to 25 w %, more preferably 10 to 20 w % most preferably 12 to 18 w % oftotal solids of the total combination. The hypophosphite may be includedin the size composition and/or binder composition and/or as a separatecomponent part of a multi-part sizing composition.

The size composition advantageously comprises a film formingpolyurethane, preferably polyester or polyether based polyurethane. Itimproves the chopping of the fibers after treatment. It further tends toreduce the coupling agent's tendency to crosslink between fibers thusmaintaining the fibers in bundles of individual fibers. A preferredpolyether based PU is Baybond PU406; a preferred polyester based PU isBaybond VPLS2277.

These polymers are advantageously used as water emulsions or dispersion.The polyurethane is selected based on its compatibility with the matrix.It could be non-ionic or anionic if sufficiently stable in theformulation.

The binder composition advantageously also comprises a polyurethanepolymer in order to enhance compatibility with the matrix resin,preferably as a non-ionic emulsion or anoinic dispersion. A preferredpolyurethane polymer suitable for the binder composition consists in apolyester based polyurethane, such as Baybond VPLS2277.

When the sizing composition is a multi-part composition, the relevantparts may be prepared in a manner known in the art by addition intowater in relevant proportions leading to the desired final sizingcomposition of the invention. It is within the skill of the relevantartisan to prepare such compositions of optimum quality under mostadvantageous conditions. The ratio between the different parts may varyas follows (in parts by weight):

-   -   Size composition: 0.06 to 0.30 parts by weight of active solid        on fibers    -   Binder composition: 0.10 to 1.40 parts by weight of active solid        on fibers    -   Sodium hypophosphite: 0.125 to 0.25 parts by weight of active        solid on fibers.

Total active solids on fibers may vary from 0.285 to 1.70% by weight offibers.

A multi-part sizing composition offers the advantage of allowingtreatment of substrate in a more efficient manner but also withdifferent components at different times and places in the productionchain. The size composition may for instance advantageously be applieddirectly after fiber substrate formation, and preferably before thefibers are collected into strands, while the binder composition may beapplied after chopping of the continuous fiber substrate, that is thestrands. The size composition then is advantageously applied by anyconventional means such as roll, dip-draw, slide or spray applicators.The sized strands may then be chopped into segments as is conventionalin the art, and the binder composition may then be applied to thechopped segments which may for instance be pelletized in any suitablemethod known to the one skilled in the art, such as tumbling in apelletizer, for instance a rotating drum equipped with a sprayer for thebinder composition. It is also within the skill of the artisanknowledgeable in this art to adapt the pelletizing conditions, includinghumidity and temperature to the requirements of the final product to beobtained. Generally a drying step is required before the chopped fiberstrands are stored prior to integration into a polymer matrix in theform of granules. The granules may then be melted in an injectionmachine for use in molding a reinforced composite article.

While the hypophosphite may be included in either of the sizecomposition or the binder composition or in both, it is preferred if thesaid hypophosphite is applied as an overcoat after application of thebinder composition to the fiber substrate, most preferably after dryingof the fibers. In the alternative, the hypophosphite may be included inthe size composition and/or in the binder composition and as a separateindividual overcoat. The preferred embodiments have shown the bestresults with respect to the characteristics of the final reinforcedproduct, that is resistance to staining, mechanical characteristics,including elongation at break, and antistatic positive effect. It hassurprisingly been found that while humidity is known to reduce themechanical properties of a fiber reinforced polyester resins, thepresence of a certain degree of residual humidity resulting from theapplied hypophosphite solution on the dried fibers goes with an increaseof mechanical properties, more specifically tensile elongation at break,when a hypophosphite is used according to the invention.

When seeking to overcome some at least of the above mentioned problems,it has been found that the sizing compositions of the invention areparticularly effective. Processability of the mineral charges,preferably glass fibers, has been significantly improved with reducedfuzz formation and reduced electrostatic charge accumulation.

The advantages of the compositions and other aspects of the presentinvention will become more apparent in the following Examples.

For the sake of clarity, LOI means Loss-on-Ignition. This definition isgenerally known to the skilled person and is used to measure thepercentage of organic solid matter deposited on glass fiber surfaces.LOI is measured herein according to ASTM2854. Strictly speaking, the LOIdefinition does not include hypophosphite salts as these are generallynot considered organic chemistry. Wishing to express the quantity ofhypophosphite salt deposited on the glass fibers, the authors haveincluded the quantity of hypophosphite salt into the LOI percentage,when appropriate.

In order to be able to include into the LOI percentage the percentage ofhypophosphite salt deposited on the glass fibers, it was necessary tomeasure it. The authors have thus developed a conductivity based methodto determine the quantity of hypophosphite salt deposited on the fibers.The method is explained hereafter with respect to sodium hypophosphite.

NaH2PO2.H2O is generally available as 50% aq solution. Its molecularweight is 106; the molecular weight of the anhydride is 88. Conductivityof several solutions with different concentrations of NaH2PO2.H2O wasmeasured by different devices and different operators and a mean linearcorrelation established. In order to determine the % of salt monohydratedeposited on chopped fiber strands:

-   -   Weight 20 g (+/−0.1 g) chopped fibers    -   Add 80 g (+/−0.1 g) demineralized water (Water conductivity        checked to be lower than 10 μs/cm)    -   Stir manually and measure conductivity after at least 5 minutes        by placing electrode in water above the fibers    -   repeat the same exercise and take the average    -   plotting the measured conductivity on the linear correlation        established for sodium hypophosphite monohydrate indicates the %        NaH2PO2.H2O added onto the fibers.

It had been found that certain prior art reinforcing fiber chargestreated with sizing compositions comprising a silane coupling agent,polyether or polyester based polyurethane and an epoxy novolac typebinder showed a tendency to fuzz formation, more specifically inpneumatic transport and feeding equipment. Fuzz formation increases therisk of filter clogging and requires increased maintenance.

An equipment was designed in order to be able to evidencestatic/antistatic properties of treated glass fiber segments or pellets.The equipment is schematically represented in FIG. 1. It comprises anessentially cylindrical chute 1 arranged on top of, and leadingvertically into, a fiber container 3. The top of chute 1 is equippedwith a pump 5. A valve 7 is arranged in the connection between chute 1and container 3. Another valve 9 is arranged in the bottom of container3; it is normally closed and may be opened to empty container 3. Twoopposite collector plates 15 of about 240 cm² are arranged vertically inchute 1. A flexible tube 11 with inner diameter of 50 mm and a length ofabout 188 cm is connected between the slightly conical bottom ofcontainer 3 and the top of conical chute 1, in the area of the collectorplates 15. The whole inner circuit is essentially airtight. A filter 13is arranged between the top of chute 1 and the pump 5.

A load of 2.5 kg of chopped coated glass fiber pellets to be tested wascharged from the top, into container 3, chute 1 unmounted, valve 9closed. Chute 1 was then tightly fixed on top of container 3. Anelectric tension of approximately 80 V continuous is applied betweenopposite collector plates. The pump is then operated in 50 cycles,during 15 min, as follows: the pump is operated; the fiber pellets aresucked through flexible tube 11 from bottom of container 3 and droppedinto top of chute 1 between the two collector plates 15, valve 7 closed;when container 3 is essentially empty, the aspiration is stopped andvalve 7 is opened thus allowing the accumulated fiber pellets to fallinto container 3 again; the cycle is repeated 50 times. During thisprocess, fuzz accumulates on filter 13 that filters the air prior toevacuation to the environment and statically loaded material accumulateson the collector plates 15. Further fuzz may accumulate on the walls ofthe flexible tube and of the whole equipment. Fuzz accumulated on thefilter, tube wall and on the collector plates may be weighted, thusgiving a measure of fuzz formation and static/antistatic properties. ARothschild Static Voltmeter R-4021 was used to measure the alternatingstatic voltage, the amplitude of which varies with charge variations atthe measuring input.

Without being bound by theory, it is believed that the presence ofhypophosphite as per the invention regulates remaining moisture on fiberto a level that participates in procuring the advantageouscharacteristics of the invention, like the anti-static effect and themechanical characteristics including more specifically tensileelongation at break. This is the more surprising as the presence ofwater is known to reduce polyester molecular weight and hence itsmechanical properties.

EXAMPLES Example 1 Preparation of a Size Composition

The components of a size composition for use in accordance with thepresent invention are set forth in Table 1 below.

TABLE 1 Material Kg/1000 L Solid content A1100 10.345   58%* PU40646.377 34.5% water Add up to 1000 L A1100 is anamino-propyl-triethoxy-silane coupling agent Baybond PU406 (Bayerproduct) is a polyether based polyurethane *understood to mean silaneactive solid partially condensed after hydrolysis

A first polyurethane premix was prepared by diluting at ambienttemperature in a first container 46.377 kg PU406 in water. A secondpremix was prepared by diluting at ambient temperature 10.345 kg of anamino-propyl-triethoxy-silane coupling agent in a second container inwater and stirring for approximately 30 minutes. The contents of bothcontainers were then combined and the volume brought to 1000 L byaddition of water.

Example 2 Preparation of an Alternative Size Composition

The components of an alternative size composition for use in accordancewith the present invention are set forth in the following Table 2.

TABLE 2 Material Kg/1000 L Solid content A1100 10.700   58%* K-12 0.50088.8%   FS-300 0.339 40% water Add up to 1000 L A1100 is anamino-propyl-triethoxy-silane coupling agent K12 is a cationic softenercomprising an acetic acid salt of the reaction product of ethylenepentamine and stearic acid Zonyl FS-300 is a fluoroalkyl alcoholsubstituted polyethylene glycol wetting agent *understood to mean silaneactive solid partially condensed after hydrolysis

The individual components were advantageously diluted under agitation inwater at ambient temperature and were then combined in a main tank understirring and the total volume of the size composition was brought to1000 L by addition of water. It is noted that this composition containsno polyurethane or other film forming agent.

Example 3 Preparation of a Binder Composition

A binder composition was prepared with the components of Table 3 below.

TABLE 3 Material Kg/100 L Solid content Nx962D 20.9 40% Nx8294 15.1 55%EMX-063 15.1 55% NaH2PO2•H2O  6.0 100%  (as received) water Add up to100 L Neoxil 962D is a non-ionic aqueous emulsion of an epoxy-esterresin (DSM) Neoxil 8294 is a non-ionic aqueous emulsion of a flexibleepoxy-ester resin (DSM) EMX-063 is a non-ionic aqueous emulsion of anepoxy film former with a 55% non-volatile fraction and 6.3 epoxyfunctionality

The above cited polymer emulsions were mixed under stirring at ambienttemperature and the relevant amount of sodium hypophosphite pre-dilutedwas added and the total volume brought to 100 liters, thus with a totalsolids content of 31%.

Example 4 Sizing of Glass Fibers

Advantex E-type glass was molten and fibers were formed by drawingfilaments through a die plate. Drawing speed and die opening areselected in order to produce fibers having an average diameter of about10 μm. A sizing composition comprising a combination of the sizecomposition of Example 1 and the binder composition of Example 3 in aratio of 10 L of size of Example 1 with approx. 3.3 L of binder ofExample 3, was then applied by a conventional kiss roll on the filamentsproduced and cooled by water vapor, at a temperature of approx. 25° C.,before same were gathered into strands and chopped into segments ofdesired length and dried for later use in PBT articles. The fibers thusobtained conferred particularly good mechanical properties, morespecifically good tensile elongation at break, to a sample of PBTcomprising 30 w % of glass fibers. In addition, the chopped fibersegments were less prone to electro-static charging and showed a muchreduced tendency to fuzz formation.

Example 5 Sizing of Glass Fibers with a Two-Part Sizing Composition

The advantages of the present invention will become even more apparentwith a multi-part sizing composition applied in accordance with theinvention.

The size composition of Example 1 was applied to E-type glass fibers asproduced in a continuous process, at the exit of a conventional dieplate, after cooling at a temperature of approx. 25° C., with aconventional kiss-roll applicator. The size composition was applied at arate such as to achieve a strand total LOI (Loss on Ignition) of 0.22%solid on the glass fibers. Residual humidity was controlled at about 10to 13% of the weight of the coated glass.

The glass fibers were then collected into strands and chopped intosegments of desired length according to a conventional manufacturingprocess. The chopped segments were dried and conveyed to a pelletizer inwhich the binder composition of Example 3 has been applied by sprayingat a rate such as to achieve 0.17 w % sodium hypophosphite anhydride (or0.2 w % sodium hypophosphite monohydrate) on the treated fibers. Glassfiber segment pellets were thus formed and conveyed to a fluidized beddryer and dried to a residual moisture content of approx. 0.05%.

The fibers thus obtained conferred particularly good mechanicalproperties, more specifically good tensile elongation at break, to asample of PBT comprising 30 w % of glass fibers. In addition, thechopped fiber segments were less prone to electro-static charging andshowed much reduced tendency to fuzz formation. These characteristicsare of enormous advantage in handling such fiber segments prior toincorporation into appropriate resin material, such as PBT.

Example 6 Preparation of a Three-Part Sizing Composition and Sizing ofGlass Fibers Therewith

In the course of a conventional glass fiber manufacturing process, asize composition as per Example 1 was applied by a conventional kissroll applicator after fiber formation (average diameter of about 10 μm)through a conventional die plate and cooling, as described in Example 5.The size composition was applied at a rate such as to achieve a strandtotal LOI (Loss on Ignition) of 0.22% solid on the glass fibers. Theresidual humidity at that stage was about 10 to 13 w % of the weight ofthe coated glass.

The glass fibers were then collected into strands and chopped intosegments of desired length according to a conventional manufacturingprocess. The chopped segments were conveyed to a pelletizer in which abinder composition prepared as per example 3 but without sodiumhypophosphite, with the following components:

-   -   20.9 kg NX 962 (at 40 w % solid)    -   15.1 kg NX8294 (at 55 w % solid)    -   15.1 kg EMX-063 (at 55w % solid)    -   Water to add up to a total volume of 100 L was applied by        spraying at a rate such as to achieve 1% LOI on the fibers. The        thus treated fibers are then transported on a conveyor belt into        a dryer for drying and curing the treated fibers. Residual        moisture content was set at approx. 0.05%. After this drying        step, the fiber segments were sprayed with a 50% solution of        sodium hypophosphite monohydrate, thus applying a rate of 0.2 w        % LOI monohydrate (or 0.17 w % LOI sodium hypophosphite        anhydride) onto the fibers. The residual moisture content was        approx. 0.2%.

The fibers thus obtained conferred particularly good mechanicalproperties, more specifically a good tensile elongation at break, to asample of PBT comprising 30 w % of glass fibers. The advantageousantistatic properties noticed before were most pronounced when workingaccording to this process as compared to the results obtained accordingto Example 5.

Example 7 Further Three Part Sizing Compositions

Further exemplary sizing compositions are illustrated in Table 4 below.

TABLE 4 material Comp G Comp H Comp I Size Ex1 at 0.22% LOI 0.22% LOI0.22% LOI Binder(100 L) 0.78% LOI 0.78% LOI 0.78% LOI Nx962D 20.87 kgNx8294 15.20 kg 15.20 kg EM-054 16.70 kg Hexion4254 13.40 kg NX429815.20 kg FILCO 345 45.70 kg water to 100 L to 100 L to 100 L NaH2PO2•H2O0.2% LOI 0.2% LOI 0.2% LOI Neoxil 962D is a 40% non-ionic aqueousemulsion of an epoxy-ester resin (DSM) Neoxil 8294 is a 55% non-ionicaqueous emulsion of a flexible epoxy-ester resin (DSM) EM-054 is a nonionic emulsion of epoxy film former with a 50% non-volatile fraction and6.3 epoxy functionality, from Adeka Hexion RSW-4254 is a 62 w %non-ionic multifunctional epoxy novolac resin dispersion by HexionSpecialty Chemicals. Neoxil 4298 is 55% non-ionic aqueous emulsion of anepoxy bis phenol A type resin with Tg of 30° C. (DSM) Filco 345 is a 55w % non-ionic epoxy novolac EPN resin emulsion by Coim spa

The size composition of Example 1 was applied to the drawn AdvantexE-glass fibers as described above, at a rate of 0.22% LOI. The bindercomposition (prepared with the concentrations of constituents asindicated in Table 4 above) was applied on chopped fiber strands in apelletizer as described earlier above at a rate such as to achieve theindicated % LOI on glass fibers. The sodium hypophosphite monohydratewas applied at the indicated % LOI after drying of the chopped andpelletized fiber strands.

Example 8 Further Three Part Sizing Compositions

Further exemplary sizing compositions are illustrated in Table below.

TABLE 5 Comp A Comp B Comp L Comp M Comp N Comp O Size at 0.22% 0.22%0.22% 0.22% 0.22% 0.22% Ex1 LOI LOI LOI LOI LOI LOI Binder at 0.67%0.67% 0.78% 0.78% 0.78% 0.67% (100 L) LOI LOI LOI LOI LOI LOI -Nx962D 16.63 kg  16.63 kg  12.4 kg -Nx8294  12.13 kg  12.13 kg   9.0 kg-EMX063   13.3 kg -Filco  26.13 kg  29.4 kg 345 -Hx4254  26.00 kg  12.13kg   9.0 kg -1037   8.3 kg -FS300 0.0067 kg 0.0067 kg .005667 kg 0.0053kg 0.0053 kg 0.0067 kg -2277  5.667 kg  5.667 kg 3.8667 kg -water to toto to to to 100 L 100 L 100 L 100 L 100 L 100 L NaH2PO2•H2O 0.2% LOI0.2% LOI 0.2% LOI 0.2% LOI 0.2% LOI 0.2% LOI Neoxil 962D is a 40%non-ionic aqueous emulsion of an epoxy-ester resin (DSM) Neoxil 8294 isa 55% non-ionic aqueous emulsion of a flexible epoxy-ester resin (DSM)EMX063 is non-ionic emulsion from Adeka of a epoxy film former with a55% non-volatile fraction and 6.3 epoxy functionality Filco 345 is a 55w % non-ionic epoxy novolac EPN resin emulsion by Coim spa HexionRSW-4254 is a 62 w % non-ionic multifunctional epoxy novolac resindispersion by Hexion Specialty Chemicals. RESYN 1037 is a non-ionicsilane modified vinyl acetate copolymer emulsion with 55 w % solids(Vinamul Polymers) Zonyl FS-300 is a 40% fluoroalkyl alcohol substitutedpolyethylene glycol wetting agent Baybond VPLS 2277 is a 40.5% emulsionof a polyester based polyurethane (Bayer)

The size composition of Example 1 was applied to the drawn AdvantexE-glass fibers as described above, at a rate of 0.22% LOI. The bindercomposition (prepared with the concentrations of constituents asindicated in Table 5 above) was applied on chopped fiber strands in apelletizer as described earlier above at a rate such as to achieve theindicated % LOI on glass fibers. The sodium hypophosphite monohydratewas applied at the indicated % LOI after drying of the chopped andpelletized fiber strands.

Example 9 Further Three Part Sizing Compositions

Further exemplary sizing compositions are illustrated in Table 6 below.

TABLE 6 C1 C2 C3 C4 C5 C6 C7 C8 C9 Size 0.06% 0.06% 0.06% 0.06% 0.06%0.06% 0.06% 0.06% 0.06% Ex2 at LOI LOI LOI LOI LOI LOI LOI LOI LOIBinder 0.99% 0.99% 0.99% 0.73% 0.99% 0.99% 0.99% 0.99% 0.99% (100 L) LOILOI LOI LOI LOI LOI LOI LOI LOI -Nx962D 17.5 kg 16.4 kg 15.4 kg 20.8 kg15.4 kg 15.4 kg 15.4 kg  8.7 kg -Nx8294 12.7 kg 11.9 kg 11.2 kg 15.2 kg11.2 kg 11.2 kg 11.2 kg 12.7 kg 19.0 kg -2277  9.9 kg 13.0 kg 16.0 kg14.5 kg  9.9 kg  9.9 kg -EM-054 14.0 kg 13.1 kg 12.3 kg 16.7 kg 12.3 kg12.3 kg 12.3 kg 21.0 kg 21.0 kg -RSC825  1.7 kg  1.7 kg -RSC1187 13.1 kg11.9 kg -water To To To To To To To To To 100 L 100 L 100 L 100 L 100 L100 L 100 L 100 L 100 L NaH2PO2•H2O 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2%0.2% 0.2% at LOI LOI LOI LOI LOI LOI LOI LOI LOI Neoxil 962D is a 40%non-ionic aqueous emulsion of an epoxy-ester resin (DSM) Neoxil 8294 isa 55% non-ionic aqueous emulsion of a flexible epoxy-ester resin (DSM)Baybond VPLS 2277 is a 41% emulsion of a polyester based polyurethaneEM-054 is an epoxy film former with a 50% non-volatile fraction and 6.3epoxy functionality, from Adeka Baybond RSC 825 is 35 w % PU crosslinkerblocked by caprolactame, available from Bayer Baybond RSC 1187 is 50 w %polyether/polycarbonate based polyurethane by Bayer

The size composition of Example 2 was applied to the drawn AdvantexE-glass fibers as described above, at a rate of 0.06% LOI. The bindercomposition (prepared with the concentrations of constituents asindicated in Table 4 above) was applied on chopped fiber strands in apelletizer as described earlier above at a rate such as to achieve theindicated % LOI on glass fibers. The sodium hypophosphite monohydratewas applied at a rate of 0.2% LOI after drying of the chopped andpelletized fiber strands.

Example 10 Preparation of Test Samples and Mechanical Properties

Chopped glass fiber segments with an average diameter of approximately10 μm and an average length of about 4.5 mm were pelletized, dried andsized in accordance with the invention with the following compositions:

-   -   Prior art composition;    -   Compositions A of Example 8,    -   Composition B of Example 8.

The prior art composition comprised a size composition as per Example 2at 0.06% LOI and a binder composition at 0.99% LOI comprising 44.65 kgNeoxil 962, 32.47 kg Neoxil 8294, 10.45 kg Baybond VPLS 2277 and waterto add up to 100 L. No NaH2PO2.H2O was added.

The above compositions were compounded with PBT Ultradur B4520 (by BASF)resin in a twin screw extruder ZSK26 Mc (by Coperion) at a throughput of30 and 80 kg/h. In order to achieve the respective throughput, therotation speed was set at about 300 rpm and at about 1000 rpm,respectively, thus achieving a torque of about 80% of maximum torque.The recorded melt temperature of the resin was 270-300° C. The glassfiber pellets and the resin were fed at a rate such as to achieve a 30 w% glass loading in the extruded product. The extrudate was a glass fiberreinforced composite rod having a diameter of approx. 2.5 mm. Theextrudate rod was cooled in a 2 m, long water bath set at 50° C.following immediately the extrusion die. The extrudate strand was thenchopped in 3.4 mm length in order to form granules.

The thus produced granules were then fed to an injection moldingequipment, Arburg 420C All Rounder 800-250 equipped with an Axxicon ISOnormalized mold, in order to produce standardized test samples asrequired for the following standard tests:

-   -   Tensile strength, modulus, elongation at break according to ISO        527-4/1/5    -   Unnotched Charpy impact strength according to ISO 179-1/1Eu,    -   Notched Charpy impact strength according to ISO 179-1/1Ea,    -   Notched Izod impact test according to ISO 180/A,    -   Color parameters on Minolta 508 according to ASTM D1925; The        injection speed was set at 30 ccm/s, at a temperature of between        275 and 230° C. with a mold temperature controlled at 80° C. The        injection pressure was recorded as follows:

TABLE 7 Test sample code Coating/throughput Injection pressure 1 Priorart/30 kg/h 1138 bar 2 Prior art/80 kg/h  658 3 Comp A/30 kg/h 1143 4Comp A/80 kg/h  716 5 Comp B/30 kg/h 1119 6 Comp B/80 kg/h  695

The thus produced samples (dry as molded) were left to catch thelaboratory temperature for 48 hours at 23° C. in a closed vessel

The samples thus produced were then used in the following testsperformed at a room temperature of 23° C. and relative humidity of 40%.

Unnotched Charpy Test

samples Test sample Av glass % tested Mean KJ/m2 Stand dev 1 30.11 1079.163 1.664 2 29.92 10 74.729 2.574 3 29.83 10 81.786 3.213 4 29.79 1073.985 3.703 5 29.97 10 78.261 3.240 6 29.93 10 74.758 2.618

Notched Charpy Test

samples Test sample tested Mean KJ/m2 Stand dev 1 10 10.505 0.335 2 109.360 0.417 3 10 10.723 0.590 4 10 9.319 0.282 5 10 10.893 0.526 6 108.847 0.454

Notched Izod Test

samples Test sample tested Mean KJ/m2 Stand dev 1 10 11.965 0.718 2 99.295 0.340 3 10 12.157 0.619 4 10 9.422 0.332 5 10 11.724 0.428 6 109.037 0.309

Tensile Strength Test

samples Test sample tested Mean MPa Stand dev 1 5 136.200 0.339 2 5139.380 0.327 3 5 132.720 0.444 4 5 135.760 0.288 5 5 132.000 0.235 6 5135.880 0.239

Tensile Modulus

samples Test sample tested Mean MPa Stand dev 1 5 10587 490 2 5 10341466 3 5 9722 106 4 5 9943 118 5 5 9649 85 6 5 9753 116

Tensile Elongation at Break

samples Test sample tested Mean % Stand dev 1 5 3.4920 0.3104 2 5 3.52000.0752 3 5 4.2120 0.0756 4 5 4.0160 0.1097 5 5 4.2660 0.1566 6 5 3.93800.1441

Length of fibers were found to be consistently within the range of250-260 μm.

Color Parameters

Yellowing index Test sample ASTM D1925 1 21.71 2 24.42 3 13.91 4 17.63 510.66 6 15.69

Example 11 Effect of Sodium Hypophosphite on Tensile Elongation at Breakof PBT Samples

When studying the addition of sodium hypophosphite to sizingcompositions, it has been found that the Tensile Elongation at Break ofPBT samples reinforced with such sized glass fibers evolves according tothe curve of FIG. 2, with a maximum between about 0.15 and 0.25% LOI(sodium hypophosphite monohydrate) on fibers.

Standard test sample preparation has been described in Example 10. Thereinforced PBT resin used is the same as the one used in Example 10. Theconcentration of sodium hypophosphite monohydrate has been variedbetween 0 and 0.25% LOI on the fibers.

 represents the tensile elongation at break of a normalized PBT samplereinforced with 30% glass fibers (TEB30N) sized with the prior artcomposition of Example 10;

▪ represents the variation of the tensile elongation at break of anormalized PBT sample reinforced with 30% glass fibers sized with theinvention composition X as a function of varying hypophosphite contentin % LOI; and

⋄ represents the variation of the tensile elongation at break of anormalized PBT sample reinforced with 30% glass fibers sized with theinvention composition Y as a function of varying hypophosphiteconcentration in % LOI.

Invention Composition X

Size applied at 0.21% LOI A187 (as received) 5.04 kg Acetic acid toadapt pH to 4 Water to add up to 100 l Binder applied at 0.84% LOINeoxil 962D 16.9 kg Neoxil 8294 12.3 kg EM-054 13.5 kg VPLS 2277 26.3 kgWater to add up to 100 l Hypophosphite: varying concentrations

Invention Composition Y:

Size applied at 0.1664% LOI A1100 (as received)  0.2 kg K12  0.01 kgZonyl FS300 0.006 kg VPLS 2277  0.55 kg Water to add up to 100 l Binderapplied at 0.84% LOI Neoxil 962D 19.57 kg Neoxil 8294 14.24 kg EM-05415.66 kg VPLS 2277  3.73 kg Water to add up to 100 l Hypophosphite:varying concentrations

Example 12 Preparation of Test Samples and Properties

Chopped glass fiber segments with an average diameter of approximately10 μm and an average length of about 4.5 mm were pelletized, dried andsized in accordance with the invention with the following compositions:

-   -   Prior art composition ref A;    -   Prior art Composition ref B    -   Invention sample 3    -   Invention sample 4    -   Invention sample 5

The prior art composition comprised a size composition as per Example 2at 0.06% LOI and a binder composition at 0.99% LOI comprising 44.65 kgNeoxil 962, 32.47 kg Neoxil 8294, 10.45 kg Baybond VPLS 2277 and waterto add up to 100 L. No NaH2PO2.H2O was added. Advantex glass fibers weresized with the prior art composition and compounded with PBT; sampleswere taken from the beginning of the compounding trial, “Ref A”, andfrom the end of the compounding trial, “Ref B”.

Invention samples 3, 4 and 5 correspond to three different Advantexglass fiber production batches obtained after sizing with composition Aof Example 8.

The above treated glass fibers were compounded with PBT Ultradur B4520(from BASF) resin in a twin screw extruder ZSK26 Mc (by Coperion) at athroughput of 30 and 80 kg/h. In order to achieve the respectivethroughput, the rotation speed was set at about 300 rpm and at about1000 rpm, respectively, thus achieving a maximum torque of about 80% ofthe maximum admissible torque of the machine. The recorded melttemperature of the resin was about 270° C. and 300° C., respectively,for 30 and 80 kg/h throughput. The glass fiber pellets and the resindried for 10 hours at 140° C. in a Motan air drier (molecular sievedried air) were fed at a rate such as to achieve a 30 w % glass loadingin the extruded product.

The extrudate was a glass fiber reinforced composite rod having anaverage diameter of approx. 2 mm. The extrudate rod was cooled in a 2 mlong water bath regulated at 50° C. following immediately the extrusiondie. The extrudate strand was then chopped in 3.4 mm length in order toform granules.

The thus produced granules were then fed to an injection moldingequipment, Arburg 420C All Rounder 800-250 equipped with an Axxicon ISOnormalized mold, in order to produce standardized test samples asrequired for the standard tests. The injection speed was set at 30ccm/s, at a temperature of between 275 and 230° C. with a moldtemperature controlled at 80° C. The injection pressure was recorded asfollows:

TABLE 8 Test sample Injection code Coating/throughput pressure 498 Priorart ref A/30 kg/h 1122 499 Invention 3/30 kg/h 1139 500 Invention 4/30kg/h 1140 501 Invention 5/30 kg/h 1141 502 Prior art ref B/30 kg/h 1110503 Prior art ref A/80 kg/h 673 504 Invention 3/80 kg/h 697 505Invention 4/80 kg/h 702 506 Invention 5/80 kg/h 681 507 Prior art refB/80 kg/h 720

The thus produced samples (dry as molded) were left to take thelaboratory condition for 48 hours at 23° C. in a closed vessel.

The samples thus produced were then used in the following testsperformed at a room temperature of 23° C. and relative humidity of 46%for tensile strength and 39% for impact tests.

Unnotched Charpy Test (ISO 179-2/eU)

samples Test sample Av glass % tested Mean KJ/m2 Stand dev 498 29.79 1070.628 2.326 499 29.81 10 73.019 4.883 500 29.75 10 75.283 2.835 50129.59 10 74.847 3.733 502 30.21 10 68.110 1.290 503 29.73 10 63.2544.155 504 29.63 10 66.989 2.071 505 29.71 10 65.158 3.347 506 29.79 1065.117 4.668 507 29.22 10 59.712 5.843

Notched Charpy Test (ISO 179-1/1eA)

samples Test sample tested Mean KJ/m2 Stand dev 498 10 8.1980 0.6543 49910 7.8630 0.5464 500 10 7.7960 0.7950 501 10 7.9450 0.7513 502 10 9.01500.6945 503 10 7.8990 0.3939 504 10 7.3910 0.2930 505 10 7.4060 0.3694506 10 7.3740 0.4184 507 10 7.7140 0.4474

Notched Izod Test (ISO 180-1/A)

samples Test sample tested Mean KJ/m2 Stand dev 498 9 9.2844 0.3853 49910 9.5370 0.6852 500 10 9.2970 0.5967 501 10 9.2710 0.6562 502 10 9.66100.6541 503 10 7.7510 0.2084 504 10 7.1630 0.1766 505 10 7.2440 0.1961506 9 7.5400 0.4227 507 10 7.5361 0.3676

Tensile Strength Test

samples Test sample tested Mean MPa Stand dev 498 9 139.278 0.222 499 10135.610 0.288 500 10 134.310 0.515 501 10 133.940 0.324 502 10 138.4900.277 503 10 146.420 0.215 504 10 140.070 0.254 505 10 138.790 0.367 50610 139.320 0.305 507 10 141.890 0.502

Tensile Modulus

samples Test sample tested Mean MPa Stand dev 498 9 10085.0 71.3 499 109875.5 73.6 500 10 9782.6 81.2 501 10 9678.4 61.4 502 10 10047.9 69.8503 10 10307.0 100.1 504 10 10126.8 67.7 505 10 10075.1 68.9 506 1010052.6 79.4 507 10 9984.3 92.4

Tensile Elongation at Break (ISO 527-4/1/5)

samples Test sample tested Mean % Stand dev 498 9 3.3667 0.1108 499 104.1330 0.1152 500 9 4.1478 0.1440 501 10 4.1570 0.1083 502 10 3.36600.1569 503 10 2.9580 0.0742 504 10 3.3600 0.1112 505 10 3.4150 0.1038506 9 3.2989 0.0715 507 10 2.8140 0.1842

Length of fibers were found to be consistently within the range of270-330 μm.

Fuzz Evaluation

Initial loads of 2.5 kg chopped coated glass fiber pellets treated withdifferent compositions were charged from the top, into container 3,chute 1 unmounted, valve 9 closed. Chute 1 was then tightly fixed on topof container 3. An electric tension of approximately 80 V continuous wasapplied between opposite collector plates. The pump was operated in 50cycles, during 15 min. During this process, fuzz accumulates on filter13 that filters the air prior to evacuation to the environment andstatically loaded material accumulates on the collector plates 15. Fuzzaccumulated on the filter and on the collector plates was collectedmanually and each time weighted and computed as a percentage of theinitial 2500 g loaded into the apparatus, thus giving a measure of fuzzformation and static/antistatic properties.

In addition, static voltage was measured by a Rothschild StaticVoltmeter R-4021 and plotted in a diagram.

For evaluation of fuzz formation, ambient temperature and relativehumidity are of significant importance and are thus shown as recorded inthe relevant tables below.

TABLE 9 Fuzz on Fuzz on Fuzz Static Static sample Filter g Wall g tot %V max Mean V ° C./% RH Pr art 11.5 2.5 0.56 49.5 13.7 23.7/31 Pr art13.9 2.3 0.65 66.1 32.6 23.7/31 Inv 3 16.8 0.6 0.70 26.8 15.8 24.0/32 Prart 15.4 2.8 0.73 45.0 22.8 24.1/34 Inv 4 17.1 0.7 0.71 23.1 13.524.5/35 Pr art 16.3 4.3 0.82 43.1 22.2 24.2/36 Inv 5 16.7 0.5 0.69 15.08.2 23.4/38

As can be seen from Table 9 hereabove, the invention size compositionsimprove the antistatic properties of treated fibers. Fibers treated withthe invention composition generate far less fuzz accumulated on thewalls of the apparatus. Also, the mean voltage and voltage extremes arefar higher for prior art size compositions than for inventioncompositions; also the static voltage curve as a function of time allalong the 50 cycles in the course of the test, is far more regular forinvention size compositions than known compositions.

Example 13

The following sizing compositions were prepared for comparison purposes:

Prior Art Composition:

Size of Example 1 at 0.22% LOI Binder (for 100 l) at 0.83% LOI Neoxil962D 20.87 kg Neoxil 8294 15.13 kg EM 054 16.67 kg Water to add up to100 L

Invention Composition:

Size of Example 1 at 0.22% LOI Binder (for 100 l) at 0.83% LOI Neoxil962D 20.87 kg Neoxil 8294 15.13 kg EM 054 16.67 kg Water to add up to100 L 50% solution of NaH2PO2 at 0.2% LOI (monohydrate)

The size compositions were applied by a conventional kiss rollapplicator after Advantex glass fiber formation (average diameter ofabout 10 μm) through a conventional die plate and cooling, as perExample 5. The size composition was applied at a rate so as to achieve astrand total LOI of 0.22% solid on the glass fibers. The residualhumidity at that stage was approximately 10-13 w % of the weight ofcoated glass. The glass fibers were then collected into strands andchopped into segments as described above. The chopped segments werepelletized with concomitant spraying of the above shown bindercomposition at a rate such as to achieve a fiber solid (% LOI) of 0.83,thus a total solid on fiber of (0.22+0.83) 1.05%. The treated fibers arethen transferred to a drying and curing step with the residual moisturebeing brought down to approx. 0.05%.

In the case of use of the invention composition, the hypophosphite issprayed after this drying step with concomitant increase of residualmoisture.

The thus treated fibers were compounded with PBT Ultradur B4520 as perExample 10 in order to ultimately form the required test samples with aglass content of 30%. The extruder used was a Werner and Pfleiderer ZSK30 machine set at a throughput of 30 kg/h, rotation speed of about 400rpm, melt temperature of about 330° C. The extrudate rod of approx. 2.5mm diameter was cut into granules having a length of approx. 3.4 mmwhich were then fed to the Arburg injection molding equipment used inExample 10 in order to produce standard test samples as requested forthe relevant tests.

Injection pressure Prior art 887 bar Invention 961 bar

Tensile Strength

Nbr of samples MPa Stand dev Prior art 10 143.42 0.84 invention 9 138.140.59

Tensile Modulus

Nbr of samples MPa Stand dev Prior art 10 11141 490 invention 9 11174158

Tensile Elongation at Break

Nbr of samples % Stand dev Prior art 10 3.4680 0.1639 invention 9 3.64780.1648

1-17. (canceled)
 18. An aqueous sizing composition for reinforcingcharges, the aqueous sizing composition comprising: a silane couplingagent; a binder composition comprising an epoxy film forming polymer,wherein the epoxy film forming polymer is compatible with thermoplasticpolyester matrix resin and comprises from 2 to 8 reactive epoxy groupsper chain; and a hypophosphite at a concentration ranging from 5 to 30weight percent of total solids of the aqueous sizing composition. 19.The aqueous sizing composition of claim 18, wherein the silane couplingagent is a functional silane present at a concentration ranging from 1to 20 weight percent of the total solids of the aqueous sizingcomposition.
 20. The aqueous sizing composition of claim 19, wherein thefunctional silane is selected from the group consisting of an aminofunctional silane coupling agent, an epoxy based silane coupling agent,and combinations thereof.
 21. The aqueous sizing composition of claim18, wherein the epoxy film forming polymer is present at a concentrationranging from 25 to 80 weight percent of the total solids of the aqueoussizing composition.
 22. The aqueous sizing composition of claim 18,wherein the hypophosphite is a hypophosphite salt selected from thegroup consisting of: a metal hypophosphite, an alkaline earth metalhypophosphite, an ammonium hypophosphite, and combinations thereof. 23.The aqueous sizing composition of claim 18, further comprising a filmforming polyurethane polymer selected from the group consisting of apolyether based polyurethane, a polyester based polyurethane, andcombinations thereof.
 24. The aqueous sizing composition of claim 23,wherein the film forming polyurethane polymer is present at aconcentration ranging from 10 to 50 weight percent of the total solidsof the aqueous sizing composition.
 25. The aqueous sizing composition ofclaim 18, further comprising a surfactant selected from the groupconsisting of octylphenol ethoxylate, ethylene oxide/propylene oxideblock copolymers, fluoroalkyl alcohol substituted polyethylene glycol,and combinations thereof.
 26. The sizing composition of claim 18,further comprising a polyoxyalkylene-amine lubricant.
 27. The aqueoussizing composition of claim 18, wherein the binder composition issubstantially free of silane coupling agent.
 28. The aqueous sizingcomposition of claim 18, wherein at least a portion of the hypophosphiteis present in the binder composition.
 29. A reinforcing charge coatedwith the aqueous sizing composition of claim
 18. 30. The coatedreinforcing charge of claim 29, wherein the aqueous sizing compositionis present at a concentration ranging from 0.4 to 1.4 weight percent ofthe coated reinforced charge, as measured by loss on ignition.
 31. Areinforced resin matrix comprising a thermoplastic polyester polymerselected from the group consisting of polybutylene terephthalate,polyethylene terephthalate, and combinations thereof, and the coatedreinforced charge of claim
 29. 32. A process for coating a reinforcingcharge comprising: applying the aqueous sizing composition of claim 18to a reinforcing charge at a concentration ranging from 0.4 to 1.4weight percent, as measured by loss on ignition, wherein the aqueoussizing composition is applied using a technique selected from the groupconsisting of rolling, brushing, spraying, and combinations thereof. 33.The process of claim 32, wherein the silane coupling agent of theaqueous sizing composition is applied to the reinforcing charge, in afirst step, prior to the application of the binder composition and thehypophosphite, wherein the said silane coupling agent is applied in anamount sufficient to provide a concentration ranging from 0.06 to 0.3parts by weight of active solids present on the reinforcing charge andwherein, in a second step, the binder composition and the hypophosphiteare respectively applied in an amount of binder composition sufficientto provide a concentration ranging from 0.1 to 1.4 parts by weight ofactive solids present on the reinforcing charge and in an amount ofhypophosphite sufficient to provide a concentration ranging from 0.125to 0.25 parts by weight of active solids present on the reinforcingcharge.
 34. The process of claim 32, wherein: the silane coupling agentof the aqueous sizing composition is applied to the reinforcing charge,in a first step, prior to the application of the binder composition andthe hypophosphite, wherein the silane coupling agent is applied in anamount sufficient to provide a concentration ranging from 0.06 to 0.3parts by weight of active solids present on the reinforcing charge, in asecond step, the binder composition is applied in an amount sufficientto provide a concentration ranging from 0.1 to 1.4 parts by weight ofactive solids present on the reinforcing charge and, in a third step,the hypophosphite is applied separately in an amount sufficient toprovide a concentration ranging from 0.125 to 0.25 parts by weight ofactive solids present on the reinforcing charge.
 35. An aqueous sizingcomposition for reinforcing charges, the aqueous sizing compositioncomprising: a silane coupling agent at a concentration ranging from 1 to20 weight percent solids; a binder composition comprising an epoxy filmforming polymer, wherein the epoxy film forming polymer is compatiblewith thermoplastic polyester matrix resin and comprises from 2 to 8reactive epoxy groups per chain, and wherein the binder composition ispresent at a concentration ranging from 25 to 80 weight percent solids;and a hypophosphite in an amount sufficient to provide a concentrationof hypophosphite ranging from 5 to 30 weight percent solids; wherein theweight percents are per total solids of the aqueous sizing composition.36. A reinforcing charge coated with the aqueous sizing composition ofclaim 36.